Ultraviolet irradiation is used in some operating rooms to decrease intraoperative wound infection. Halogenated hydrocarbons are commonly used as anesthetic agents and are known to undergo photodecomposition. We have shown that: 1) Halothane is decomposed by UV irradiation to several decomposition products, of which CF3COCl, CF2 double bond CHCl, CF3-CH2Cl, Br2, and F- have been identified. Others are under investigation. 2) Halothane decomposition products are toxic, causing a high mortality in mice following short-term exposure (100 to 200 ppm for 1 to 3 hours). Serum enzymes SGOT and SGPT are increased and cytochrome P450 and b5 contents are decreased when mice are exposed to UV-irradiated halothane. 3) UV irradiation of halothane in O2 forms more toxic decomposition products than irradiation of halothane in nitrogen or air. RESEARCH OBJECTIVES: a) To determine the dose-response relationship of chronic exposure to subanesthetic levels of halothane and its photodecomposition products to several parameters of toxicity in mice. b) To assess the toxicity of individual decomposition products formed by UV irradiation of halothane in mice. c) To sample the atmosphere in non- and UV-irradiated operating rooms and then determine the concentrations of halothane and its decomposition products to which personnel are exposed. d) To develop a methodology for measuring pentane and other volatile by-products of lipid peroxidation in human breath samples and evaluate the use of these techniques as a predictive tool for determining the predisposition of patients to halothane hepatotoxicity.